A user equipment (UE) in a non-dedicated connection state can obtain, only through a random access process, a resource for sending uplink data. In an enhanced random access process, when selecting an access signature, the UE selects a resource for sending data transmission subsequently. A network side device determines, according to a mapping between a signature and a resource, a resource accessed by the UE. A resource corresponding to a signature is called a default resource. After the network side device detects a UE that performs random access, if it is determined that a default resource applied for by the UE is not occupied, that is, the default resource applied for by the UE is available, the network side device grants a resource to the UE by using acknowledgement (ACK) information in an acquisition index (AI). The UE sends data by using the granted default resource.
In the prior art, in a common enhanced dedicated channel (Common E-DCH) feature, a mapping between a signature and a default E-DCH resource is defined in the following formula (1):X=SigInd mod Y  (1)
where X is a default E-DCH resource index, Y is the total number of E-DCH resources in a cell that can be used for enhanced uplink access in a cell forward access channel (Cell_FACH) state and in an idle state, and SigInd is the Sth signature allocated to the enhanced uplink access in the cell, which is numbered from zero (0).
The default E-DCH resource is actually a Common E-DCH resource. Configuration information of the Common E-DCH resource is included in the standard protocol 25.331: Common E-DCH system info 10.3.6.9a, which currently supports a maximum of 32 sets of resources, and a serial number (or called an index (index)) corresponding to each set of resources is a sequence of the resources that appear in the configuration information. If the default resource applied for by the UE is not occupied, the network side device allocates the default Common E-DCH resource to the UE to perform data transmission.
The foregoing mapping between the default E-DCH resource and the signature is calculated based on a feature that currently, a common enhanced dedicated channel (Common E-DCH) is designed to support only one physical random access channel (PRACH).
After the cell forward access channel state is further enhanced, a signature allocated to the enhanced uplink access in the cell is further divided, and multiple PRACH channels are introduced. The signature and a PRACH channel are used to indicate a capability of the UE during the random access. When the signature allocated to the enhanced uplink access in the cell is further divided and multiple PRACHs are introduced, a default resource corresponding to each signature and each PRACH channel is not defined, so that the UE cannot know, during the random access, a resource corresponding to a selected random access parameter and finally cannot complete a random access process effectively.
If the foregoing formula (1) continues to be used to configure a mapping between the signature and the default E-DCH resource, multiple different random access parameters (that is, a Signature and a PRACH) may correspond to a same set of default resources, so that a conflict probability increases and network access efficiency of the UE is reduced; or when the UE selects some random access parameters to compete for a 2 ms resource, it actually obtains a 10 ms resource, so that the UE cannot perform data transmission correctly.